Samarium Sm 153 Lexidronam Pentasodium and 3-Dimensional Conformal Radiation Therapy or Intensity-Modulated Radiation Therapy in Treating Patients With Rising Prostate-Specific Antigen Levels After Radical Prostatectomy for Prostate Cancer

DISEASE CHARACTERISTICS: Inclusion criteria: * Histologically proven diagnosis of prostate cancer progressing after prior radical prostatectomy as indicated by one of the following: * Postoperative prostate-specific antigen (PSA) rising above 1.0 ng/mL * Postoperative PSA rising above 0.2 ng/mL with a surgical tumor Gleason score of 9 or 10 * Postoperative PSA rising above 0.2 ng/ml with nodal disease * Stage II-IV disease (T2 -T4, N0-N1) * No distant metastases based on the following minimum diagnostic work up: * History or physical examination within the past 8 weeks * Bone scan negative for bone metastases within the past 4 months * Abdominal imaging negative for metastases within the past 6 months Exclusion criteria: * Biopsy evidence of M1 disease * Presence of neuroendocrine features in any prostate cancer specimen PATIENT CHARACTERISTICS: Inclusion criteria: * Zubrod Performance Status 0-1 * Absolute neutrophil count (ANC) ≥ 1,800 cells/mm³ * Platelet count ≥ 100,000 cells/mm³ * Hemoglobin ≥ 8.0 g/dL (transfusion or other intervention to achieve Hgb ≥ 8.0 g/dl is permitted) Exclusion criteria: * Prior invasive malignancy (except nonmelanoma skin cancer) unless disease free for a minimum of 3 years * Severe, active comorbidity, defined as follows: * Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months * Transmural myocardial infarction within the last 6 months * Acute bacterial or fungal infecti…